Switching mechanism.



G. A. BALS.

SWITCHING MECHANISM.

APPLICATION FILED JUNE 24, 1912.

Patented July 428, 1914-.

2 SHEETSSHEET 1.

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G. A. BALS.

SWITCHING MECHANISM.

APPLICATION FILEDVJUNE-M, 1912.

Patented July 28, 191 1 2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

CHARLES A. B-ALS, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, ,TO FRANK B. COOK COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

SWITCHING MECHANISM.

Specification of Letters Patent.

Application filed June 24, 1912. Serial No. 705,413.

To all whom it may concern;

Be it known that 1 CHARLES A. BALS, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Switching Mechanism, of which the, following is a full, clear, concise, and exact description, reference being had to the accompanying drawings,

forming apart of thisspecification.

[My invention rel tes to intercommunicating telephone systems and' particularly to switching apparatusthat is of particular service in connection with such systems.

I will explain my invention more fully by reference to the accompanying drawings showing the preferred form of the invention as it is embodied in connection with one type of intercommunicating telephone systems and in which Figure 1 is a diagrammatic view of an intercommunicating system; Fig. 2 isa view in elevation, partially in section. of my improved switching mechanism; Fig. 3 is a view on line 3 3 of Fig. 2; Fig. 4 is a plan view of the structure shown in Fig. 3, partially in section; Fig. 5 is a view on line 5 5.

of Fig. 3; Fig. dis a view on line 66 of Fig-3. I

Like parts are indicated by similar characters of reference throughout the different figures.

I will first describe the circuit arrangement illustrated in Fig. 1 and which shows three'stations A, B, C, the' apparatus at each of which including a telephone receiver 1, a telephone transmitter 2, a telephone switch hook 3 for including the telephone transmitter and receiver in circuit with and exeluding from the circuit of telephonic conductors 4 and 5 which are extended into multiple connections with the contact springs 6 and 7 of keys 8 (individual to each of the lines extending to the stations where such keys are located) when the key 9 is in the position indicated at station B. Each of the keys 8 at each of the stations is provided with contacts 10 and 11 which are normally separated from the contacts 6 and 7 but which are, respectively, engaged thereby when the key 8 at a station which is calling any of the other stations of the intercom'municating system Or any station which is called from an exchange is depressed, it being assumed'that a line called from an exchange is free for selection or that the called intercommunicating line is free for appropriation by the calling'intercommunieating party.

lVhen the telephonic equipment at an intercommunicating station is thus brought into telephonic connection with any telephone line extending to such station, such telephone equipment is held in this relationship (while the receiver is oil its hook)'by means of the dog 12 that engages a lug Patented July 28, 1914.

13 provided upon the key 9, such engageg ment being illustrated at station B. Each dog 12 is pivotally mounted upon a swinging plate 14 which is engageable by a pin 15 provided upon the lower end of each-bar 16. The bar 16 at'each station is provided with pins 17 that are worked upon by the keys 8 when the keys are depressed. The equipment at station A is in conditionto permit the keys 8 thereat to be depressed. hen a key thus free to be depressed is so depressed, the free end of the plate 14 is engaged under the lug carried by the upper end of the armature 18 as illustrated at station B whereby the element of key 19 (which moves bodily with the plunger element 9 and is ivotally mounted thereupon) is removed ii'om the path of travel ofthe plunger element of the key 9 whereby the lug 13 is free to ride under the dog 12 so that the nose of said dog will engage the lug, as illustrated at station B, to hold the key in its depressed position as is necessary in the establishment of telephonic c'onnection between the associate telephone set 1, 2 and the line towhich the actu ated key 8 is individual.

The tele honic connection thus mechanically held 1s adapted to be broken by the associate magnet 20 which, when energized, swings the armature 18to break the engagement between the armature and the associate plate l l whereuponthe dog 12 carried by such plate is raised out of engagement with the lug 13 to permit the plunger element of the key 9 automatically to be thrust back so as to break" the previously held telephonic connection. To this end the magnet 20 at one or more of the vstations (the equipment now to be described being shown at station A only) is provided with a controlling circuit and suitably associated switching mechanism, such circuit being traceable from the lower pole of the battery 52, the winding of magnet 20, the now engaged contacts 22-, 23,

, 30 and which bridge conductor includes a magnet 28. \Vhen the magnet 28 isenergiz'ed upon the closure of the contacts 26, 27

(which'closure is effected when the closure of contacts 24 and 25-is effected with the results stated) contacts 31 and 32 are closed for the purpose of maintaining the continuity of the bridge conductor through the winding 28 when the holdingkey lever 33 is released. The armature of the magnet 28 may be provided with a visual signal attachment 34 to indicate to the operator Whether or not the trunk line is held; The trunk line extends to an exchange (which need not be illustrated) the bridge whichis established through the magnet28 replacing the bridge that was previously established across the trunk line through the telephonically released equipment 1, 2. The magnet 28 is in high resistance so that when'the telephone equipment 1, 2 is. again bridged across the trunk line the magnet will be shunted as a consequence of the comparatively low resistance of the bridge conductor including the elements 1 and 2.

The purpose of the holding magnet 28 is to maintain the equipment that is associated with the trunk line at the exchange to which the trunk line extends in status guo whether such trunk line extends to an exchange where it is either manually orautomatically extended or not.

As the circuit arrangement is illustrated in Fig. 1', station B hascalled station Aand the latter station has responded. Station C has the key or button 17 connected to the line .from station-A depressed, the apparatus at station 0 being in condition to enable the party thereat to test the A line. The operator at station B in order to signal station A depresses the key 9 to its innermost limit to bring the contacts 35 together whereby signalin circuit is established which may be traced from the upper terminal of the sig naling battery 36 through the signal receiver 37 at the ealled station, through the contacts 38, the lower contacts of the switch hook 3 when electrically connected by said switch hook when supporting its associate telephone receiver 1, the conductor 39, the lower line side of the called line, the engaged contacts 7, 11 of the key 8 at the calling station which is then depressed,the contacts 35 at the calling station, to the lower side of the battery, 36. I have described the system 1 controls the ringing, testing, and talking circuitsis mounted upon the upper end of a vertically movable plate 9 that constitutes a plunger, this plunger carrying the Wedging devices 45 for working the circuit controlling springs 23, 46 that are to be controlled thereby. A dog 19 (Fig. 5) is pivotally mounted upon the plunger 9 which is pressed upon by a spring 48, this spring 48 (when free so to do) pressing the lower end of the dog 19 into the stationary slot 49 for the purpose of preventing the plunger 9 from being depressed. When the plunger has been depressed and is free to be elevated a restorinospring .50 serves to effect the elevation. lqormally the element 19 is in engagement with the slot 49; If the line' wanted is busy, then the plunger can only be slightly depressed to a testing position (station C, Fig. 1), as the magnet 20 will be energized. In the testing operation the key 8 at the testing station is fully depressed, fully-to depress the corresponding bar 16, whereby the bar is brought into the path of the armature 40, the bar 16, through the intermediation of the pin 15, bringing the upper end of the plate 14 into line with the recess 51 inthe armature 40. If the tested line is busy the ma net 20 at the testing station will be energize to withdraw the portion 18 of the armature 40 out of engagement with the upper end of the plate 14 so that the spring 48 will be free to move the dog 19 into ongagement with the slot 49 after the actuated button 8 at the testing station is released, the reenga ementof the dog 47 being effecte'd before he plunger 9 is depressed, this depressionbeing efi'ected after the key 8 at the testing station has been released. If the plunger 9 is arrested by the portion of the dog 19 that enters the slot 49, then the testa ing party will know that the tested line is busy. The circuit that is established for the magnet 20 when it is thus connected with the tested busy line may be traced from the lower'pole of the battery 52 through the winding of magnet 20 at the testing station, the testing contacts 53 that are engaged when a button 8 at the testing station is fully depressed, the contacts 54, the contacts 7 and 11 of the fully depressed button 8 at the testing station, the upperportion of the conductor 39 at the station being tested, a con- If the tested line is idle, the magnet at tact 55 and acontact 46 engaging the same,

the switch hook 3 at the station of the busy line, the telephone receiver and transmitter at such's'tation, one of the contacts 46 and engaging contact 56 at the busy station, assuming that the button 9 at the busy station is not depressed (and that the receiver at the busy station is merely removed from its switch hook. Thence by the conductor 57 impedance'58, to the upper pole of the battery'52. The test circuit that'is present in connection with a busy station which previously sought and obtained connection with another line is apparent when it is explained that the line of the testedstation is bridged by the contacts 60 at the tested stationwhen test button 9 at the tested station is depressed.

the testing station will not be energized and the armature 40 .will therefore have its portion 18 in position to retain engagement with the upper end of the plate 14, the ,plate 14 then engaging the upper end of the dog 19 to move the'upperend of the dog inwardly against the force of the spring 48 whereby the lower end ofthe dog is maintained out of the slot 49 in which-condition of the apparatus' the plunger 9 may be fully depressed moved beneath such T-head.

i to the rlnglng position and may remain in 'its'nearly depressed position for establishing a talking circuit with the wanted station. The plunger 9 is provided with a projection 59 having a T-head which overlies the plane of movement of the bar 16 when the plunger 9 is not depressed so that the bar 16 may be When a button 8 is fully depressed (and its depression occurs before the plunger 9 is to be depressed) the bar 16 moved by the button 8 underlies the T-head of the projec= tion 59 so that the plunger 9 cannot be de-. pressed while a button 8 is fully depressed (see station 0). Thus the button 43 of the plunger 9 cannot be depressed even thou h the dog 19 is out of engagement with t e slot 49 (which is the case when the bar 16 is depressed .by a button 8, owing to the movement of the plate 14 ;by the pin 15) whereby the seeking party is prevented from operating the plunger 9 to connect his telephone with a busy line. The projection 59 is brought into line with the bar 16 when the plunger 9 is depressed to a talking position so that the bar 16 cannot be moved from its normal position by a key 8 for the purpose of bringing the telephone at the seeking station into connection, it being necessary for the telephone receiver at a seeking station to be restored upon its switch hook before telephone connection may be established between such seeking station and a second sought line. The plunger 9, when depressed to a talking position, is maintained in such depressed condition by the dog 12 which is pressed by a spring 12 into engagement with the projection 13 see station B and Fig. 6). \Vhen the conversation is finished, circuit is established through the magnet 20 which attracts its armature 40 to disengage the armature portion 18 from the upper end of the plate 14 whereupon the spring 50 restores the plunger.

The circuit that is established through the magnet 20 when conversation is through may be traced from the lower pole of the battery 52 through-the winding of the magnet, the engaging contacts 22 and 23 (see station B) the lower contacts of the switch hook 3 at the same station with the magnet 20 then engaged by the switch hook to which the telephone receiver has'been returned, the then engaged contact to the under side of the corresponding (or home) side, the impedance 58 of such line to the upper terminal of the battery 52.

The plate 42' which supports the ma et 20, the plate 14, the armature 40,- the p un-- ger 9, the dog 12, and other parts as will beunderstood is removably secured to the framework 61 that carries the bar 16, the key mechanism 8 and the associate springs, the stems cf screws 62 being received within upwardly opening slots in the frame 61, and a groove in a post63 receiving an upright portion of the frame 61 as indicated in Fig. 5. The opening 64 in the frame 61 is sufficiently large to permit the head of key 43 to be drawn downwardly therethrough after the magnet structure and its associate parts have been moved upwardly and outwardly.

The intercommunicating telephone system herein shown .forms the subject matter of my co pending application Serial No. 705,412., filed June 24, 1912.

While I have herein shown and particularly described the preferred embodiment of my invention I do not wish to be limited to the precise details of construction or circuit, 110 arrangement shown as changes may readily be made without departing fromthe spirit of the invention, but 4 Having thus described my invention I claim as new and desire-to secure by Letters 115 Patent the following 1. Switching mechanism including a switch actuated bar; a 'swingingly mounted element 14 adapted to be operated by said bar; an electro-magnet having an armature 120 serving, when unattracted,to hold the element 14against movement, the bar serving to bring said element 14 into engagement with the armature; a switch; and means whereby "said element 14.holds the switch in 126 an actuated position when said element 14 is held by the armature.

2. Switching mechanism including a switch actuated bar; a swingingly mounted element 14 adapted to be operated by said 130 bar; an electro-magnet having-an armature serving,whenunattracted, to hold the element '14 against movement, the bar Serving to bring the element 14' into engagement with "the armature; a: switch; .and a dog whereby the element 14 holds the switch in an actuated-position whensaid element 14 is held by the armature.

'3.- Switching mechanism including a switch actuated bar; a swingingly mounted element 14-adapted to be operated by said bar; an electro-magnet having anarmature serving to hold the element 14 against move ment, the bar serving to bring saidelement 14 into engagement with the armature; a switch; and means whereby said element 14 holdsthe switch in an actuated position when said element 14.is held by the armature.

I 4. Switching mechanism including a switch actuated bar; aswingingly mounted element 14 adapted to'be operated by said bar; an electro-magnet having an armature serving to hold the element 14 against movement, the bar serving to bring the ele ment 14 into engagement with the armature;

a. switch; and a dog whereby the element 14 holdsthe switch in \anactuated position when said element 14 is held by the armature.

'5. Switching mechanism including a switch-actuated barta swingingly mounted element 14 adapted'to be operated by said bar; an electro-magnethaving an armature serving, when unattracted, to hold the element 14 against movement, the bar serving to bring said element 14 into engagement with the armature; a switch; and a-dog for engaging the switch to prevent its movement and ,released from "engagement with the switch by said element whenv held by the armature;

'bar1;.-an 'electro-inagnet having an armature serving, nwhen unattracted, to hold the element 14 againstmovement, the bar serving to bring said element 14 into engagement with the armature; a switch ;'and a dog normally engaginglthe switch to prevent its movement and disengaged from the switch by said element 14 when said element 14 is engaged by the armature.

8. Switching mechanism including a switch actuated bar; a swingingly mounted elementl4adapted to be operated by said bar; an electro-magnet having, an armature serving to hold the element 14 against movement; the bar serving to bring said? element 14 into engagement with the armature; a switch; and a dog normally engaging the switch to prevent its movement and disengaged from the switch by said element 14 when said element 14 isengaged by thearmature.

In witness. whereof, I hereunto subscribe my name this" twentieth dayofMay A. D.,

CHARLES A. BALS. Witnesses- 

